Drilled rivet holes between existing rivets in bottom spar cap according to upgrade instructions. Removed top wing skin and de-burred the holes drilled in the added extruded angle on the top spar cap and the holes in the bottom spar cap. Installed rivets in the bottom spar cap holes. Reviewed work to be done to the rear spar and remainder of the work to do on the upgrade. Noted that many of the existing rivet holes in the top wing skin and leading edge skin appear to be too big. They measure between 0.175" and 0.185" in diameter for the #5 Avex rivets. The Zenith specs for the max size of these holes is 0.189" so many of these holes are very near the max size and doesn't seem right to me. I don't know exactly how to fix this or if it needs fixing. I could use 3/16" rivets or double up on the rivets to put a new rivet with proper sized hole between the existing large hole rivets.
